oh-my-opencode/packages/omo-codex/plugin/components/telemetry/src/posthog-activity-state.ts

import { existsSync, mkdirSync, readFileSync } from "node:fs";
import { join } from "node:path";

import { writeFileAtomically } from "./atomic-write.js";
import { getActivityStateDir } from "./data-path.js";

export type PostHogActivityState = {
	readonly lastActiveDayUTC?: string;
};

export type PostHogActivityCaptureState = {
	readonly dayUTC: string;
	readonly captureDaily: boolean;
};

const POSTHOG_ACTIVITY_STATE_FILE = "posthog-activity.json";

function getPostHogActivityStateFilePath(): string {
	return join(getActivityStateDir(), POSTHOG_ACTIVITY_STATE_FILE);
}

function getUtcDayString(date: Date): string {
	return date.toISOString().slice(0, 10);
}

function isPostHogActivityState(value: unknown): value is PostHogActivityState {
	return value !== null && typeof value === "object" && !Array.isArray(value);
}

function readPostHogActivityState(): PostHogActivityState {
	const stateFilePath = getPostHogActivityStateFilePath();

	if (!existsSync(stateFilePath)) {
		return {};
	}

	try {
		const stateContent = readFileSync(stateFilePath, "utf-8");
		const stateJson: unknown = JSON.parse(stateContent);

		if (!isPostHogActivityState(stateJson)) {
			return {};
		}

		return stateJson;
	} catch {
		return {};
	}
}

function writePostHogActivityState(nextState: PostHogActivityState): void {
	const stateDir = getActivityStateDir();
	const stateFilePath = getPostHogActivityStateFilePath();

	try {
		mkdirSync(stateDir, { recursive: true });
		writeFileAtomically(stateFilePath, `${JSON.stringify(nextState, null, 2)}\n`);
	} catch {
		return;
	}
}

export function getPostHogActivityCaptureState(now: Date = new Date()): PostHogActivityCaptureState {
	const state = readPostHogActivityState();
	const dayUTC = getUtcDayString(now);
	const captureDaily = state.lastActiveDayUTC !== dayUTC;

	if (captureDaily) {
		writePostHogActivityState({
			...state,
			lastActiveDayUTC: dayUTC,
		});
	}

	return {
		dayUTC,
		captureDaily,
	};
}